Roller clutches that operate between a cam race and a pathway race must be installed between the races at some point, an operation that is often done manually. Installation is eased by the fact that the rollers and springs of the clutch are usually retained to a clutch cage as a secure subassembly that can be handled and installed as a unit. Still, situations may arise where roller clutches designed for conventional installation may be difficult to handle.
Conventional roller clutch installation typically involves the initial step of installing the clutch to the cam race alone. This allows the pathway race to be added last by the so called ringing in technique, in which it is simultaneously pushed and twisted into place, which serves to set the rollers and springs in a proper operating position. The clutch itself is also generally installed to the cam race with a push and twist technique, sometimes called the twist lock method. However, the pushing and twisting motions are not simultaneous, as when the pathway race is rung in. An example of a clutch cage designed for twist lock installation to a cam race is disclosed in U.S. Pat. No. 4,712,661 to Lederman et al. Clutch 10 has a cage 12 molded with smaller reaction ears 44A on the lead axial side, and larger reaction ears 44B on the trailing axial side. Each reaction ear 44A and 44B is also axially adjacent to a sloped reaction face that is shaped to abut with a similarly sloped cam hook 26C on the cam race 22. To install clutch 10, cage 12 is first turned relative to cam race 22 to a point where the lead side reaction ears 44A will fit past the peak of the cam hooks 26C. Next, cage 12 is pushed axially over cam race 22 until the reaction ears 44A and 44B are both axially aligned with the end faces of the cam race 22. Finally, cage 12 is twisted through a small angle until the reaction faces are abutted with the cam hooks 26C, completing the installation to the cam race 22.
The twist lock installation method works best when the installer can see the cam race well. The installer can then see when the cage has been moved to the point where the reaction ears will clear the cam race, allowing the cage to be pushed on. It is also important that the installer be able to maintain a grip on the cage throughout the process, so that the final twist that brings the reaction faces up against the cam hooks can be easily applied. There may be situations where both visual and physical access are limited. For example, the cam race may be surrounded by other structure that blocks a clear view. The clutch may have to be inserted into an area where it becomes difficult to do anything more than push the clutch cage straight in once it has been inserted beyond a certain point, and even the pushing force may have to be applied indirectly. Such blind assembly situations do not work well with a cage designed for twist lock installation.